Composition and method of using perlite

ABSTRACT

The present invention relates to a powder adhesive composition comprising: (a) cement; (b) a dispersible polymer powder; and (c) at least 10% volume of the powder adhesive is an expanded perlite; wherein said cement is at a ratio of between 600-1000% of the mass of the expanded perlite; and wherein the powder adhesive composition is an adhesive, and the adhesion strength of the adhesive, is over 0.4 MPa, after 28 days, and after water immersion for at least 20 days.

TECHNICAL FIELD

The present invention relates to the use of compositions containingexpanded perlite. More particularly, the present invention relates tothe use of compositions of expanded perlite for the constructionindustry.

BACKGROUND

Volcanic glass, such as perlite, forms when molten rock, i.e. lava,pours out of a volcano and rapidly cools. That rapid cooling inhibitscrystal formation and permitting water to escape. Perlite is the lavathat hardens immediately and contains 2-5% water.

Perlite is known in industry in two forms: crude and expanded. Crudeperlite is prepared by the crushing and screening of perlite intovarious sized fractions. Expanded perlite is perlite after it has beenheated. When heated, perlite can expand to as much as twenty times itsoriginal volume. This expansion is the result of heated water: when theglassy lava rock is heated to, for example, 890° C., the water moleculestrapped in the rock turn into vapor which causes the rock to expand.That is similar to water that expands, when heated, in a corn kernel tocreate popcorn. It is the presence of these trapped water molecules inperlite which accounts for the physical properties of expanded perlite.

Expanded perlite can be manufactured to weigh between 32-240 kg/m³,making it adaptable for numerous applications in the construction,industrial, chemical, horticultural and petrochemical industries.

U.S. Pat. No. 7,736,574 discloses a method for the production of perliteproducts such as sheets, panels or bricks. The disclosed method involvesfirst providing a quantity of expanded perlite and treating the perliteby applying a cement binder thereto, so as to at least partiallyencapsulate the perlite with binder. Thereafter, an amount of cement isadded to the binder-treated perlite and a mixture is created. Thedescribed mixture is then formed and allowed to harden to yield solidarticles. Nevertheless, the disclosed method is used for yieldingperlite based solid articles.

SUMMARY

It is an object of the present invention to provide a light weightcomposition for use in the construction industry.

It is another object of the present invention to provide a light weightadhesive, for attaching any natural or synthetic stone veneer.

It is still another object of the present invention to provide anecological adhesive for gluing stone tiles, which has a long open time.

It is still another object of the present invention to provide anadhesive or plaster which has improved thermal and acoustic insulatingproperties.

Other objects and advantages of the invention will become apparent asthe description proceeds.

The present invention relates to a powder adhesive compositioncomprising: (a) cement; (b) a dispersible polymer powder; and (c) atleast 10% volume of the powder adhesive is an expanded perlite; whereinsaid cement is at a ratio of between 600-1000% of the mass of theexpanded perlite; and wherein the powder adhesive composition is anadhesive, and the adhesion strength of the adhesive, is over 0.4 MPa,after 28 days, and after water immersion for at least 20 days.

Preferably, the composition further comprises a cellulose etherscompound.

Preferably, the composition further comprises a defoamer.

Preferably, the composition further comprises a fiber compound.

Preferably, the cement is white cement.

In one embodiment, the cement is Portland cement.

In one embodiment, the composition further comprises an accelerator.

Preferably, the expanded perlite comprises at least 1% of the total massof the composition.

Preferably, the dispersible polymer powder is a dispersible powder basedon vinyl acetate.

Preferably, the fiber compound is a polypropylene compound.

Preferably, the adhesive composition is used for gluing a tile.

Preferably, the adhesive composition is used for gluing a stone tile.

Preferably, the adhesion strength of the adhesive, is between 0.5-1.5MPa, after 28 days, and after water immersion for at least 20 days.

The present invention also relates to a method of producing a powderadhesive comprising the steps of: mixing expanded perlite, cement, and adispersible polymer powder, in any order; wherein at least 30% volume ofthe sand-free powder adhesive is the expanded perlite.

The present invention also relates to a powder adhesive compositionwhich comprises: gypsum; a retarder; a dispersible polymer powder basedon vinyl acetate; and wherein at least 30% volume of the powder adhesiveis an expanded perlite.

Preferably, the retarder is a modified polymer retardation.

DETAILED DESCRIPTION

Prior stone veneer powder adhesives, such as Sika Ceram-202,manufactured by Sika AG of Switzerland, or Mr. Fix 116 manufactured byCarmit Mr. Fix Ltd., of the United Kingdom for gluing ceramic tiles,typically have a density of more than 1400 kg/m³. The heavy weight ofthese prior adhesives is due, inter alia, to the weight of the sand inthe adhesive. The heavy weight of these prior adhesives is costly interms of transportation and problematic in terms of handling, e.g.manual carrying. Furthermore, if the sand is not dried properly, beforeit is mixed into the adhesive, some of the adhesive's polymers can beruined, effectively weakening the adhesive.

The term “adhesive” is meant to include hereinafter any composition thathas an adhesion strength, after 28 days, of more than 0.4 megapascal(MPa).

Adhesive/Plaster Composition

An adhesive/plaster composition is proposed, for use in the constructionindustry, which uses expanded perlite. Unlike conventional adhesivecompositions having sand as aggregate; in this embodiment, the volume ofsand is substituted with an equal or equivalent volume of expandedperlite. In some versions, the adhesive is sand-free. The composition,which comprises expanded perlite, may be used for creating an adhesive,plaster, or any kind of material that hardens on drying and may be usedfor indoor and/or outdoor gluing on and/or coating walls, ceilings,floors, or for any other construction use. For example, the compositionmay be used as a powder adhesive, when mixed with water the resultingmaterial can be used for gluing natural or synthetic stone tiles to awall. Thus, for example, a powder adhesive composition for a stoneveneer, which uses expanded perlite instead of sand, may have a densityof approximately 500 kg/m³, which results in a lighter weight, for thesame volume, compared to a typical prior powder adhesive that may have adensity greater than 1400 kg/m³. In one embodiment the Density (dry mix)of the powder adhesive composition may be between 250-1500 kg/m³. Inanother embodiment the Density (dry mix) of the powder adhesivecomposition may be between 350-1500 kg/m³. The advantages of usingexpanded perlite instead of sand in powder adhesives or plaster in termsof improving the thermal and/or acoustic insulation properties of theadhesive and/or plaster are due to the expanded perlite's improvedthermal and/or acoustic insulation properties that are discussed furtherat Table 1. The adhesive composition, which comprises expanded perlite,may have different consistencies such as powder, granular, cream, etc.The adhesive or plaster composition, which comprises expanded perlite,may be stored in sacks, bags, buckets, or any other known container. Inparticular, the expanded perlite comprises:

-   -   at least 10% of the total volume of the adhesive/plaster        composition;    -   at least 30% of the total volume of the adhesive/plaster        composition    -   at least 70% of the total volume of the adhesive/plaster        composition;    -   at least 80% of the total volume of the adhesive/plaster        composition; or    -   at least 90% of the total volume of the adhesive/plaster        composition.        Examples of the above total volume of the adhesive/plaster        compositions are described in greater detail below.

Adhesive/Plaster Composition With Vermiculite

Alternatively, expanded vermiculite may be used instead of expandedperlite as set forth in the above-identified paragraph regarding theadhesive/plaster compositions. Vermiculite is a hydrous silicate mineralthat (a) is classified as a phyllosilicate and (b) expands greatly whenheated. Vermiculite may be formed by weathering or hydrothermalalteration of biotite or phlogopite.

Powder, Light Weight Stone Veneer Adhesive

A first powder, light weight, stone veneer adhesive has

-   -   (a) expanded perlite in at least 70 volume percent of the        adhesive;    -   (b) cellulose ether compounds at a ratio of between 7-15% of the        mass of the expanded perlite;    -   (c) a dispersible polymer at a ratio of between 17%-180% of the        mass of the expanded perlite;    -   (d) a defoamer at a ratio of between 0.5-20% of the mass of the        expanded perlite;    -   (e) a fiber compound at a ratio of between 0.9-1.1% of the mass        of the expanded perlite;    -   (f) an accelerator at a ratio of between 5-15% of the mass of        the expanded perlite; and,    -   (g) optionally, cement at a ratio of between 600%-900% of the        mass of the expanded perlite.        The components of the instant adhesive can be mixed together in        any order to obtain the desired adhesion strength, of the        adhesive, which is over 0.4 MPa, after 28 days, and after water        immersion for at least 20 days. Preferably, the adhesion        strength is between 0.5-1.5 MPa, after 28 days, and after water        immersion for at least 20 days.

A second powder, light weight, stone veneer adhesive has

-   -   (a) expanded perlite in at least 1% of the mass of the adhesive;    -   (b) cellulose ether compounds at a ratio of between 5-25% of the        mass of the expanded perlite;    -   (c) a dispersible polymer at a ratio of between 10-250% of the        mass of the expanded perlite;    -   (d) a defoamer at a ratio of between 0.1-65% of the mass of the        expanded perlite;    -   (e) a fiber compound at a ratio of between 0.6-15% of the mass        of the expanded perlite;    -   (f) an accelerator at a ratio of between 3-25% of the mass of        the expanded perlite; and,    -   (g) optionally, cement at a ratio of between 600-1000% of the        mass of the expanded perlite.        The components of the instant adhesive can be mixed together in        any order to obtain the desired adhesion strength, of the        adhesive, which is over 0.4 MPa, after 28 days, and after water        immersion for at least 20 days. Preferably, the adhesion        strength is between 0.5-1.5 MPa, after 28 days, and after water        immersion for at least 20 days.

In some embodiments, the powder, light weight, stone veneer adhesive isa sand free adhesive.

A third powder, light weight, sand free, stone veneer adhesive hasexpanded perlite in at least 10% volume of the powder adhesive;cellulose ether compounds at a ratio of between 5-25% of the mass of theexpanded perlite;

a dispersible polymer at a ratio of between 10-250% of the mass of theexpanded perlite;

a defoamer at a ratio of between 0.1-65% of the mass of the expandedperlite;

a fiber compound at a ratio of between 0.6-15% of the mass of theexpanded perlite;

an accelerator at a ratio of between 3-25% of the mass of the expandedperlite; and,

optionally, cement at a ratio of between 600-1000% of the mass of theexpanded perlite.

The components of the instant adhesive can be mixed together in anyorder to obtain the desired adhesion strength, of the adhesive, which isover 0.4 MPa, after 28 days, and after water immersion for at least 20days. Preferably, the adhesion strength is between 0.5-1.5 MPa, after 28days, and after water immersion for at least 20 days.

A fourth powder, light weight, sand free, stone veneer adhesive hasexpanded perlite in at least 15% volume of the powder adhesive;

a dispersible polymer at a ratio of between 10-305% of the mass of theexpanded perlite;

a defoamer at a ratio of between 0.1-65% of the mass of the expandedperlite; and,

optionally, cement at a ratio of between 40-1505% of the mass of theexpanded perlite.

The components of the instant adhesive can be mixed together in anyorder to obtain the desired adhesion strength, of the adhesive, which isover 0.3 MPa, after 28 days, and after water immersion for at least 20days. Preferably, the adhesion strength is between 0.5-2.5 MPa, after 28days, and after water immersion for at least 20 days

The described adhesives may be mixed with water for creating a gluehaving cream like texture, which hardens on drying. Due to the expandedperlite's intrinsic characteristics, water may be added to the powderadhesive composition in the mass ratio of approximately 0.8:1, forexample, meaning, that approximately 0.8 liter of water may be added foreach 1 kg of powder; 0.9:1; 0.7:1; 0.6:1; or 1:1. Water could also beadded to the powder adhesive composition in the ratio of between 60-100%of the mass of the powder adhesive composition. The ration of wateradded to the adhesive powder may also be a function of the specificingredients of the adhesive powder. The adhesive, with or withoutcement, may be used for gluing any stone tiles as a protective and/ordecorative covering for exterior or interior horizontal or verticalsurfaces.

The composition, comprising expanded perlite, is used for creating alightweight powder veneer adhesive. The term veneer is meant to includeany protective or ornamental facing which can be adhesively attached toany horizontal or vertical surface. The adhesive may be used foradhesively attaching stone such as granite, porcelain, ceramic, mosaic,porcelain, marble, brick, or any other synthetic or natural stone to awall, ceiling, floor or any other surface. The powder adhesive is mixedwith water for creating a cream like textured glue, which hardens ondrying. The glue may be used for adhesively attaching any stone tiles asa protective and/or decorative covering for exterior or interiorhorizontal or vertical surfaces. The powder adhesive composition, forattaching stone veneer, comprises

First Component:

-   -   at least 1% of expanded perlite of its total mass;    -   at least 3% of expanded perlite of its total mass;    -   at least 6% of expanded perlite of its total mass; or    -   at least 9% of expanded perlite of its total mass.

Preferably, the expanded perlite, used in the adhesive composition, hasthe following characteristics:

-   -   (A) a granular size of between 0.01 to 2 mm, and a density that        includes and is between 50-115 kg/m³;    -   (B) a granular size of between 2 to 6 mm and a density that        includes and is between 40-50 kg/m³;    -   (C) a granular size of between 0.01 to 6 mm and having a density        that includes and is between 40-115 kg/m³.

For example, the physical properties of the expanded perlite that can beused for creating a powder adhesive composition for attaching stonetiles is disclosed at Table 1:

TABLE 1 Spatial weight 40-115 kg/m³ Color White Refractive Index 1.4-1.5Granular Size From fine powder to 6 mm pH 7-8 Softening Point 890-1100°C. Fusion Point 1280-1350° C. Specific Heat 387 J/kg · K ThermalConductivity 0.04 W/m · K

In practice, the expanded perlite, used in the adhesive composition, canbe derived from different sources, and have other physical properties.

The use of expanded perlite instead of sand in construction compositionsmay also benefit the environment as the perlite is a natural andecological substance. The use of expanded perlite instead of sand inpowder adhesives or plaster can also improve the thermal and/or acousticinsulation properties of the adhesive and/or plaster due to the expandedperlite's improved thermal and/or acoustic insulation properties.

Second Component:

A cellulose ethers compound, preferably, Mecellose FMC 21010manufactured by Samsung Chemical; Methocel, which is water-solublemethylcellulose and has hydroxypropyl methylcellulose polymers, anyother cellulose ether that is made for use with cement and mixturesthereof. The cellulose ethers compound enhances some of the qualities ofthe adhesive composition such as providing workable quality to thecomposition and/or extending the open time of the composition, and/orimproving the water saturation of the composition, where open time isthe time after the adhesive is applied during which a serviceable bondcan be made. The cellulose ethers are added to the adhesive compositionat a ratio of between

-   -   5-25% of the mass of the expanded perlite,    -   7%-15% of the mass of the expanded perlite;    -   30-40% of the mass of the expanded perlite.

Third Component

A dispersible polymer, preferably, Wacker's Vinnapas 5025L, which is aleveling dispersible powder based on vinyl acetate and ethylene, or maybe any other dispersible powder based on vinyl acetate, or any otherhydroscopic compound which is dispersible in water, such as SBR-basedadhesives, vinyl acetate, acryl, etc. The dispersible polymer is addedto the adhesive composition at a ratio of between

-   -   10%-250% of the mass of the expanded perlite;    -   200-250% of the mass of the expanded perlite;    -   5-300% of the mass of the expanded perlite.

Fourth Component

A defoamer, e.g. an anti-foam agent, such as Vinapor® DF 9010 F, or anyother chemical additive that reduces and hinders the formation of foam.Commonly used agents are insoluble oils, polydimethylsiloxanes and othersilicones, certain alcohols, stearates and glycols. The additive is usedto prevent formation of foam or is added to break a foam already formed.Preferably, the fiber compound may be added to the adhesive compositionat a ratio of between

-   -   0.1-65% of the mass of the expanded perlite; or    -   0.5-30% of the mass of the expanded perlite.

Fifth Component

A fiber compound such as Adfil construction fibers or any otherpolypropylene compound having a fiber length of 6 mm or any otherchemical or synthetic fiber compound which may be used for cement basedadhesives, or any other fiber that is used with cement such as nylonfiber. Preferably, the fiber compound may be added to the adhesivecomposition at a ratio of between

-   -   0.6-15% of the mass of the expanded perlite; or    -   0.6-0.9% of the mass of the expanded perlite.

Sixth Component—Optional

Cement such as white cement, Portland cement, or any type of cement oraluminous cement. Preferably, the cement may be added to the adhesivecomposition at a ratio of between

-   -   600-1000% of the mass of the expanded perlite;    -   800-950% of the mass of the expanded perlite;    -   250-1700% of the mass of the expanded perlite;    -   350-900% of the mass of the expanded perlite; or    -   350-1700% of the mass of the expanded perlite.

As indicated above, the adhesive composition, comprising expandedperlite, may be free of cement. The resulting adhesive composition freeof cement is a light weight adhesive used for indoors gluing. Thisadhesive may be sold as a cream adhesive.

Seventh Component—Optional

Gypsum and a retarder such as HYCON R 7200, manufactured by BASF, or anyother modified polymer retardation instead of cement. The gypsum may beadded to the adhesive composition at a ratio of between 600-900% of themass of the expanded perlite, and the retarder may be added in relationsto the desired open time.

Eighth Component—Optional

The adhesive for attaching veneer may also comprise an additive foraccelerating the bonding time of the adhesive, referred to hereinafteras accelerator. The accelerator may be Calcium Formate, CalciumChloride, or any other additive that can be used for accelerating thebonding time of the adhesive. The accelerator may be added to theadhesive composition at a ratio of between 5-15% of the mass of theexpanded perlite.

Process Steps

The expanded perlite and all the other component ingredients, mentionedabove, of the adhesive composition, may be mixed together in any orderto form a powder adhesive composition.

The above-identified powder adhesive composition may be mixed with waterto create glue for gluing any synthetic or natural stone tile to anysurface. Due to the expanded perlite's intrinsic characteristics, watermay be added to the powder adhesive composition in the mass ratio ofapproximately 0.7:1, meaning that approximately 0.7-1 liter of water canbe added for each 1 kg of powder, to approximately 1:1. That means,water may be added to the powder adhesive composition in the ratio ofbetween 70-100% of the mass of the powder adhesive composition.Alternatively, water may be added to the powder adhesive composition inthe mass ratio of approximately 0.6:1 to approximately 1:1. In otherwords, water may be added to the powder adhesive composition in theratio of between 60-100% of the mass of the powder adhesive composition.

The resulting adhesive composition that complies with this disclosurehas an adhesion strength

-   -   (A) over 0.5 MPa, after 28 days;    -   (B) over 1 MPa, after 28 days;    -   (C) between 0.5-1.5 MPa, after 28 days,    -   (D) between 0.5-1 MPa, after 28 days,    -   (E) between 0.5-2.5 MPa, after 28 days,    -   (F) (i) over 0.5 MPa, after 28 days; over 1 MPa, after 28 days;        between 0.5-1.5 MPa, after 28 days, or between 0.5-1 MPa, after        28 days and (ii) after the adhesive has been immersed in water;    -   (G) (i) over 0.5 MPa, after 28 days; over 1 MPa, after 28 days;        between 0.5-1.5 MPa, after 28 days, or between 0.5-1 MPa, after        28 days and (ii) after the adhesive has been immersed in water        for at least 1 day; and    -   (H) (i) over 0.5 MPa, after 28 days; over 1 MPa, after 28 days;        between 0.5-1.5 MPa, after 28 days, or between 0.5-1 MPa, after        28 days and (ii) after the adhesive has been immersed in water        for at least 20 days.

The resulting adhesive composition that complies with this disclosurehas a wet density of:

-   -   (A) between 700-1400 kg/m³;    -   (B) between 800-1600 kg/m³;    -   (C) between 700-1500 kg/m³.

EXAMPLES

An adhesive example is set forth at Table 2, with ingredients and theirapproximated amounts for creating a powder adhesive composition, whichcomprises expanded perlite, for attaching stone tiles:

TABLE 2 Perlite 820 g White Cement 7.38 Kg Methocel 100 g Vinaps 5025L0.6 Kg poly propylene 10 g Vinapor DF 9010 F 50 g

By mixing the exemplified ingredients and amounts, of Table 2, then apowder adhesive composition of about 9 kg is created. Water, for exampleand not limited to 7.5 liters, is added to this powder adhesivecomposition to create a glue that is used to adhere the stone veneer ortiles to a surface after which the glue cures and the tiles stayattached to the surface henceforth.

The mixing of the exemplified ingredients and amounts identified attable 2 create an adhesive that complies with the properties C2 TE S1 ofany of the European adhesive standards: EN 1346 (2007), EN 1308 (2007),EN 1347 (2007), EN 1348 (2007), or EN 12002 (2008). Those standards areavailable on http://www.techstreet.com or http://shop.bsigroup.com.

Lab tests of the above disclosed example powder adhesive compositionreveal the following characteristics of the composition:

TABLE 3 Density (wet) 700-1400 kg/m³ Preferred Water to powder relation0.9 liter water for 1 kg powder Effective work time 90 minutes Open time30 minutes Cover capability 2.6 Kg/m² for 5 mm thickness adhesionstrength after 28 days 0.5-1.5 megapascal MPa Working temperature 5°C.-35° C.

Thus, as conveyed at Table 3, the powder adhesive composition weighsless than the typical prior art powder adhesive. That decreased weightreduces costs of transportation and handling. In addition, the use ofexpanded perlite instead of sand in the powder adhesives prolongs theopen time of the adhesive, after the water is added, effectively makingthe perlite based adhesive more comfortable for use.

Lab tests that use the above-identified powder adhesive compositionreveal the following characteristics of the composition:

TABLE 4 Density (dry mix) 250-1500 kg/m³ Preferred Water to powderrelation 1 liter water for 1 kg powder Effective work time 90 minutesOpen time 45 minutes Cover capability 2.6 Kg/m² for 5 mm thicknessadhesion strength after 28 days 0.5-1.5 megapascal MPa Workingtemperature 5° C.-35° C.

Table 4 conveys the described adhesive complies with the known adhesiveproperties of: C1, C1 T, C1 TE, C1 TE S1, C1 TE S2, C2, C2 T, C2 TE, C2TE S1, or C2 TE S2 of any of the European standards such as: EN 1346(2007), EN 1308 (2007), EN 1347 (2007), EN 1348 (2007), or EN 12002(2008) available on http://www.techstreet.com orhttp://shop.bsigroup.com.

Experimental Reports: Experiment Mo. 1:

At CN 101279833 A, Jieru described a mortar composition. Jieru's mortarcomposition is compared with this application's claimed adhesivecomposition. In particular, Jieru discloses an insulation mortar for usein masonry or plastering. Jieru's mortar is based on the compositiondisclosed in the abstract and in the summary of CN 101279833 A while theproposed adhesive is based on one of the embodiments, with theunderstanding that both compositions have the same total volume forcomparison purposes:

TABLE 5 Proposed ingredients Jieru's composition adhesive cement 4.5 Kg50% 7.240 Kg 83% coal ash 1.44 Kg 16% 0 dispersible 0.225 Kg 2.5% 0.6 Kg6.8% polymer + defoamer wood fiber 0.027 Kg 0.3% 0 fiber compound 0.009Kg 0.1% 0.015 Kg 0.17% calcium formate 0.045 Kg 0.5% 0 cellulose ethers0.054 Kg 0.6% 0.1 Kg 1.1% sulphonated 0.036 Kg 0.4% 0 polycondensahon(water repellent + multifunctional additives) expanded perlite 2.7 Kg30% 0.82 Kg 9.3%

Results:

Jieru's composition is an insulation mortar composition that has anadhesion strength between 0.07-0.1 MPa (as measured in accordance to theEN 998-1:2016 standard available athttp://www.techstreet.com/standards/bs-an-998-1-2016?productid=1936338). In contrast, the adhesion strength of the proposed adhesiveis between 0.5-1.5MPa, after 28 days, and after water immersion for atleast 20 days as measured in accordance to the EN 1348:2007 standardavailable at http://www.techstreet.com/standards/be-en-1348-2007?productid=1533195). Accordingly, Jieru's composition does not and cannot meetthe minimum requirements of the claimed invention.

Experiment No. 2:

GB 1225755 discloses a cement-based adhesive. For the sake of brevity,the Comparative Examples A-C of GB 1225755 have been tested. Thecompositions comprised the following amounts of components:

TABLE 6 Example A (kg) B (kg) C (kg) White Portland “Snowcrete” 4.414.470 4.450 Cement cimbeton cimbeton cimbeton Expanded unmilled perlite0.360 0.540 0.720 grade 100/28 agrikal agrikal agrikal PowderedLimestone 3.915 3.915 3.915 stone&lime stone&lime stone&lime Vinylacetate copolymer 0.225 0.225 0.225 5044 5044 5044 vinapas vinapasvinapas Methyl hydroxypropyl 0.090 0.090 0.090 cellulose Mp75 h Mp75 hMp75 h weikem weikem weikem Water 8.0-9.0 lt 8.0-9.0 lt 8.0-9.0 ltCement:perlite mass ratio (%) 1225 780 560

The compounds disclosed in Table 6 were compared to an example accordingto the present invention having the following amounts of components thatconform to the teachings of the claimed invention (see Table 7):

TABLE 7 Proposed adhesive Components: White Cement 7380 g Expandedperlite 850 g Vinnaps 5025L 600 g Methocel 100 g Polypropylene 10 gWater 6.5-7.0 lt Cement:perlite mass ratio (%) 870

Analysis of Compositions:

The adhesive strength of the compositions prepared above were analysedaccording to the standard EN 1348 august 2007. The extended open time ofthe compositions prepared above were analysed according to the standardEN 1346 august 2007

Results:

TABLE 8 Adhesive strength Extended open time Example (MPa) (minutes)Comparative A 0.2 in water 18 (failed) (failed all test) Comparative B0.17 in water 19 (failed) (failed all test) Comparative C 0.14 in water19 (failed) (failed all test) Present invention 1.1 in water 30 m (asnecessary)

As conveyed at Table 8, GB 1225755's cement-based adhesive fails to meetthe minimum requirements of the claimed invention.

While the above description discloses many embodiments andspecifications of the invention, these were described by way ofillustration and should not be construed as limitations on the scope ofthe invention. The described invention may be carried into practice withmany modifications which are within the scope of the appended claims.

1. A sand-free powder adhesive composition comprising: cement; adispersible polymer powder; and expanded perlite, wherein at least 10%volume of the sand-free powder adhesive is expanded perlite;characterized in that said cement is at a ratio of between 600-1000% ofthe mass of said expanded perlite.
 2. The composition according to claim1, wherein said expanded perlite has a density of between 50-115 kg/m3,and a granular size of between 0-2 mm.
 3. The composition according toclaim 1, wherein said dispersible polymer powder is at a ratio ofbetween 5-300% of the mass of said expanded perlite.
 4. The compositionaccording to claim 1, further comprising a cellulose ethers compound. 5.The composition according to claim 1, further comprising a fibercompound.
 6. The composition according to claim 1, wherein the cement iswhite cement.
 7. The composition according to claim 1, wherein thecement is Portland cement.
 8. The composition according to claim 1,further comprising an accelerator.
 9. The composition according to claim5, wherein the fiber compound is a polypropylene compound.
 10. Thecomposition according to claim 1, wherein the perlite comprises at least1% of the total mass of the adhesive composition.